The cut flower industry needs postharvest techniques that allow for extended storage of fresh cut flowers to meet consumer demands. We evaluated the use of sub-zero storage temperature (-0.6 °C) to maintain viable flowers with improved or comparable vase life to flowers stored at the industry standard (4 °C) without sacrificing aesthetic appeal. The vase life of 17 commercially important cut flower species: alstroemeria, anemone, campanula, carnation, chrysanthemum, delphinium, freesia, gerbera, gypsophila, larkspur, lily, lisianthus, ranunculus, rose, stock, sunflower, and tuberose, when stored dry at -0.6 °C for durations of 4, 8, and 12 weeks was comparable to or longer than when stored at 4 °C. Tuberose stems were not viable after holding for any storage duration or temperature. Stems of carnation benefited from an 8-hour pre-storage pulse with a hydrating solution and maintained a similar vase life to non-stored control stems when stored for 4 weeks at -0.6 °C. Conversely, rose stems only maintained similar vase life to non-stored control stems when held at 4 °C for all pre-storage pulsing solutions (water, hydration or holding solution). Vase life of lily and chrysanthemum declined for all pre-storage pulsing solutions and stems only remained viable after 8 weeks storage when held at -0.6 °C. Additionally, stored chrysanthemum and lily stems had a longer vase life when stored at -0.6 °C than when held at 4 °C after 4- and 8-weeks storage, respectively, for all pre-storage pulsing solutions. Experiment 3 further evaluated carnation, lily, and rose stems with and without a pre-storage acclimation period at 4 °C for either 24 hours or 1 week prior to extended storage durations of 4, 6, or 8 weeks. Holding stems at 4 °C for 1 week prior to extended storage reduced vase life of all species. Rose stems remained viable after 8 weeks of extended storage when held at -0.6 °C, but only when no pre-storage hold was used. Lily and rose stems were not viable beyond 4-week storage durations when held at 4 °C, but remained viable with no pre-storage holding period after 8 weeks at -0.6 °C. Carnation stems maintained longer vase life irrespective of a pre-storage holding period when stored at -0.6 °C. Through this work we show that that many species of cut flower may be held at sub-zero temperature with improved or comparable vase life to the industry standard of 4 °C.
